Lancair crash at SnF

Larry Dighera wrote in
:

On Fri, 25 Apr 2008 01:27:52 +0000 (UTC), Bertie the Bunyip
wrote in :

The best way to do it is with a steep bank. Very steep.


The bank angle may be quantified:



Good grief Larry, you really are an idiot.
Of course it can be quatified, but the numbers only tell a minute part
of the story. I can categorically state that I can do a 180 with 70 deg
bank at VSO 1.2 deadstick and come out the other end in one piece. Can
you? Try it using those figures and send my the answer via my Ouiji
board.


Bertie

Brian wrote in news:a4038f02-2e60-474d-81bc-
:


One way to practice this would be to establish a "runway altitude"
at,
say, 1000ft AGL, get the airplane into takeoff configuration on
heading
at that altitude over a road or something, simulate a failure at a
specified altitude--say, 1,500 feet--and see what altitude you're at
when you get back to your reciprocal heading. If it's above your
starting altitude, you made it.


Actually this is very similar to how I do have pilots simulate this.
However it is often not quite realistic for a couple of reasons.

1. The illusion of speed. When done for real the airplane will seem to
be fly much faster than when done close to the ground, especially if
there is much wind. I am thoroughly convinced the most stall spin
accidents happen for two reasons. A. is the illusion of speed when the
pilot thinks the are going faster than the are. B. Is the pilot isn't
thinking they are in a situation where a stall is possible, and thus
does not recognize it as a stall when it occurs. (Very similar to A)

Absolutely. Add to this the very real ( as opposed to illusory) fact
that the climb gradient is much poorer and that the wind gradient (
assuming you're climbing) is also nibbling at both airspeed and climp
performance and...

Bertie

Stefan wrote in news:23401$4811996a$54487369
:

Brian schrieb:

My mantra to pilots is "an
emergency is not the place to be practicing little used skills, try to
make an emergency landing as normal as possible"

I absolutely agree. But my conclusion is: Practice, practice, practice.
Of course this also includes discussing the options during the departure
briefing.


It's the only way to do it, but you'll still probably break your neck on
the day.


Bertie

On 2008-04-24, WingFlaps wrote:
Let's work some real numbers for a 172 at 500'. Say climb was a Vx 59
knots.

Firstly, I don't know anyone who routinely climbs out at Vx - certainly
not at 500'. Secondly, this is 100 feet below the altitude I stated.
IIRC, Vy is for a C172 is in the region of 65 knots - or best glide, and
many pilots accelerate to around 70-75kts at 500 feet to get a better
view forward, since best rate in many parts of the world isn't critical
to maintain once you're above a couple of hundred feet.

pilot carries out some trouble checks say 10s. Calls on the radio =10
s and plans his return.

The sequence is aviate, navigate, communicate. Most pilots I know won't
touch the radio with a problem at low altitude. The pilot I know who did
make the turnback from 600 feet certainly didn't, he just turned back.
However, in his situation it was pretty obvious the engine had lunched
itself so there was no time spent 'debugging' the problem. (For the
record, the only engine stoppage I had on takeoff was at 50 feet - the
decision to land straight ahead was very easy and fast to make).

Note that 20s have probably elapsed. The plane
has already travelled ~0.4 miles and at a 10:1 glide ratio has lost
200' (assuming he did get it to best glide in the first place). Can
he make 2 turns and land back -no way!

If the pilot does that, then yes - no way. However, the pilots I've know
who've had low engine failures have never yakked on the radio, nor have
they spent 10s debugging the problem!

you 35 seconds. 45 seconds lost = 450 feet! Now we add in the energy
losses from having to accelerate with the wind and to glide speed.

You do NOT have to accelerate with the wind! You are a creature of the
air, turning downwind does not involve a loss of airspeed!

I agree that the primary concern is to not stall. However, pilots must
be prepared to make a decision rather than 'default straight ahead' -
the decision, whatever it is, must be made quickly and you must not
stall. And yes, sometimes, turning back to the runway is possible and
this will depend on the situation - altitude and the suitability of
terrain, pilot proficiency etc.

When you're about to push the throttle forwards, you SHOULD have some
kind of a plan if it goes pear shaped. What's the wind doing? Is there a
crosswind? What's the terrain surrounding the airfield like? If you lose
power at point X what is the best course of action, and at point Y what
is the best course of action? The best courses of action (other than 'do
not stall') may not be a fixed prescription.

--
From the sunny Isle of Man.
Yes, the Reply-To email address is valid.

On Apr 25, 8:31*pm, Stefan wrote:
WingFlaps schrieb:

Try reading the statement again, here it is:
"Now we add in the energy losses from having to accelerate with the
wind and to glide speed."
To summarise your missed point, the pilot control inputs cost energy
that is not factored into simple glide/time analysis.

This is absolutely correct. But then, I dont understand the connection
to your first statement regarding the wind. Additioinal drag by control
input is completely unrelated to the presence or non-presence of wind.


Itls a turn upwind to downwind. That involves 2 direction changes, one
to reverse course and the the other to line up the runway. If there's
wind there will be an effect on line up. Try thinking about more
factors that cost altitude OK?

Cheers

On Apr 25, 9:31*pm, Dylan Smith wrote:
On 2008-04-24, WingFlaps wrote:

Let's work some real numbers for a 172 at 500'. Say climb was a Vx 59
knots.

Firstly, I don't know anyone who routinely climbs out at Vx - certainly
not at 500'. Secondly, this is 100 feet below the altitude I stated.
IIRC, Vy is for a C172 is in the region of 65 knots - or best glide, and
many pilots accelerate to around 70-75kts at 500 feet to get a better
view forward, since best rate in many parts of the world isn't critical
to maintain once you're above a couple of hundred feet.


I can see you missed the point entirely. By the way, Vy is never at
best glide (it is above that ~69knots in a 172) -perhaps you would
like to revise what determines Vy? My point was to ilustrate the
impossible turn with some concrete numbers instead of the handwaving
BS that seems pervasive in this topic.

Good luck on your first engine failure during climb out, if you turn
back I hope you make it. but you'll have a better chance going
straight ahead...

Cheers

.

WingFlaps schrieb:

Itls a turn upwind to downwind. That involves 2 direction changes, one
to reverse course and the the other to line up the runway. If there's
wind there will be an effect on line up. Try thinking about more
factors that cost altitude OK?

All good and fine, and I'm thinking about a lot of factors, btw. also
about human ones which are usually the weak link, but you still have not
explained what you meant when you wrote: "Now we add in the energy
losses from having to accelerate with the wind."

On Apr 25, 10:45*pm, Stefan wrote:
WingFlaps schrieb:

Itls a turn upwind to downwind. That involves 2 direction changes, one
to reverse course and the the other to line up the runway. If there's
wind there will be an effect on line up. Try thinking about more
factors that cost altitude OK?

All good and fine, and I'm thinking about a lot of factors, btw. also
about human ones which are usually the weak link, but you still have not
explained what you meant when you wrote: "Now we add in the energy
losses from having to accelerate with the wind."

Yes, I did. I'll explain it one last time. A direction change in a
plane is always due to acceleration (and that means more drag). That's
Newtonian physics. You go from up wind direction (takeoff is usually
up wind) to turn in the wind direction to land down wind. There's an
acceleration, it is a change in _velocity_ it creates drag, it costs
height and that's the important bit. Now do you understand -TURNS are
not free, they cost more height than the distance covered. Get it
now?

Cheers

WingFlaps wrote in news:ac05ca83-bbc8-4c3b-9469-
:

On Apr 25, 8:31*pm, Stefan wrote:
WingFlaps schrieb:

Try reading the statement again, here it is:
"Now we add in the energy losses from having to accelerate with
the
wind and to glide speed."
To summarise your missed point, the pilot control inputs cost
energy
that is not factored into simple glide/time analysis.

This is absolutely correct. But then, I dont understand the
connection
to your first statement regarding the wind. Additioinal drag by
control
input is completely unrelated to the presence or non-presence of
wind.


Itls a turn upwind to downwind. That involves 2 direction changes, one
to reverse course and the the other to line up the runway. If there's
wind there will be an effect on line up. Try thinking about more
factors that cost altitude OK?


It's not so much the loss of altitude that will get you in this
manuever. it's the probable loss of control trying to manuever around
back towards the field.
Firstly, in any emergency that hasnt been drilled, you will have a
moment where you will be sitting there with your mouth open in utter
disbelief of what has just happened. in fact, even if you have drilled
for it you will still have this moment, but if it's been practiced the
moment you begine to do something about it will be sooner coming.
While you're sitting there wondering what's going on, the speed will be
bleeding off. Not good. Then, you will have to manuever the airplane
around using rapid manuevering at a relatively high bank angle if you're
going to make it (I'm assuiming you're still pretty low) and if you
aren't 100% au fait with this sort of flying you're going to be very
lucky to be able to maintain control of the airplane before the ground
reaches up and smites you. This is less about the maths than the
pilot;'s proficiency. The pilot who is proficient enough to do this will
have determined an altitude above which he knows it is possible to do it
and so the question will not be one of whether it's within the
performance capabilities of the airplane, but one of whether the pilot
can accurately control the airplane through the required manuever.
Here is what you'll have to do the instant the engine gives up:
Smooothly lower the nose as you roll just as smoothly, but as quickly as
possible, towards the crosswind, if any. You will have to continue to
lower the nose as the turn, which should ideally have at least 60 deg of
bank, is completed. you should be just nibbling the stall during this,
and , needless to say, perfectly co-ordinated. Pitch control is now
critical as what you're trying to do is cheat physics by offloading the
wing as you turn. a 60 degree bank in level flight will give you a stall
speed of 1.4 VSO and you should be below that so you're right on the
edge. This is all about having very good seat of the pants capability
based on experience. As you approach the desired heading to your landing
spot, you have to smoothly roll out and get the nose up and back to a
good glide attitude. You'll have sacrificed some altitude doing the
sharp turn, but far less than you would have making a wider turn with a
gentle bank. As you level the wings, you should be on, or close to, your
desired glide speed. This is a difficult manuever to pull off. Even
practicing at a bit of altitude has some risks. you're going to pull a
bit of G and it's easy to lose the plot and either spin out of it or
overstress the airframe praciticing it unless you know what you're
doing. It's not really something that most pilots should even consider.
Someone flying 25 hours a year s unlikely ever to become sharp enough to
do this reliably. I certainly wouldn't try it now unless there was no
choice.
There's a lot of crap talked about turning back and most of the
accidents occuring as a result of this are because the pilot has heard
it's possible and decides to learn how to do it when it actually
happens. Most modern flight manuals tell you it isn't possible but this
advice is ignored by guys who reckon they're a cut above because they
did the math or tried it once or twice at altitude or because they read
about it here.



Bertie

Shirl wrote:
WingFlaps wrote:
I've also heard a lot of BS in this thread about not having good
palces to put the plane. There is nearly always somewhere flat to put
the plane within 90 degrees of the runway centerline -even a road.
Malls have big parking lots!

I don't know about where you live, but malls here have lots of light
poles, concrete islands, park-and-rest benches and ... and ... vehicles
everywhere. And having gone through it once, I'm no longer fooled by
what *looks* "flat" at 500, or even 50 feet.

I'd rather hit a bus shelter or light poles @ 40-50 MPH than go in
inverted after a stall/spin @ 200-300 AGL.